A tire in the known way comprises an internal carcass, a tread, a bead for attachment to a rim, a sidewall, and an inner liner. The internal carcass is made up of at least one carcass ply of rubber-coated threads. During a stage in the manufacture of the tire, this carcass ply is cut and assembled onto a building drum. Because this ply may make a number of turns around this drum, there are thus a plurality of layers formed from one and the same carcass ply. Now, it sometimes happens that, during the placement of the ply, the end of this ply does not coincide exactly with the start of this ply on the drum, meaning that there is a surplus of ply in the assembly. This superposition locally creates an additional thickness on the green tire. Once this green tire has been vulcanized and the resulting tire has been inflated, this additional thickness gives the appearance of a crater in the sidewall of the tire. Now, this crater is particularly visible on the tire, notably under certain lighting conditions, and may form a reason for a consumer not to purchase the tire even through this defect is not detrimental to safety. In order to mask this defect on the sidewall of the tire, according to the prior art described in U.S. Pat. No. 6,439,287, it is proposed that a moiré pattern be formed over the entire sidewall of the tire, and notably in the region where the distortion/cratering deformation created by the overlapping of the ends of the carcass ply or plies occurs. A number of moiré patterns are described. These moiré patterns constitute interference patterns notably comprising striations. Thus, these moiré patterns create interferences when light is reflected off the sidewall of the tire. The differences in light reflection that there are between the distorted/cratered region and the rest of the surface of the sidewall are thus no longer visible to the naked eye.
One problem with this prior art is that the method of manufacturing these moiré patterns is complex and costly to implement. Another problem is that the pattern does not provide the consumer with an appearance he regards as satisfactory.
That being the case, the aspects disclosed herein seek to mask this sidewall deformation defect in a way that is simpler, and to do so for the vast majority of angles from which a consumer might observe the tire.
A “tire” means any type of resilient tire whether or not subjected to an internal pressure.
The “tread” of a tire means a quantity of rubbery material delimited by lateral surfaces and by two main surfaces, one of them an inner surface and the other an outer surface, the said outer surface being intended to come into contact with a roadway when the tire is being driven on.
The “bead” of a tire means a part of the tire that is intended to be seated on a wheel rim.
The “sidewall” of a tire means a lateral surface of the tire positioned between the tire tread and a bead of this tire.
A “protruding element interpenetrating with other adjacent protruding elements” means that the spherical cap formed by the protruding element is interrupted by the other adjacent protruding elements so that the distance between the tip of the spherical cap and the tip of another adjacent protruding element is less than the diameter of this spherical cap.
A “pattern formed on a sidewall” means a sidewall part having homogeneous surface finish features that differ from the rest of the sidewalk. This pattern may deliver technical and legal information and, on the other hand, may allow consumers to discern the origin of the product.